[Formula8]

I decided to go with a cam that matches the potential of my SD CNC'd 295 KRE heads. Based on the collective experience of many on this board, I decided to not reinvent the wheel here and go with the OF cam. I have never liked hydraulic lifters so the good experience that many have had with Crower's solid rollers with HIPPA made the hybrid choice an easy one.

At this point I secured the cam and roller lifters from Paul Knippen's Muscle Motors (thanks Paul for the service and good advice). I reconfigured the IH of my 99383 springs to 1.770. This gives me a calculated spring pressures of 160lbs on the seat and open pressure of 399lbs. This matches what Dave has previously recommended and Cliff and others have been successful running. I have checked all of the clearance but visually, this cam looks like it is going to put a serious hurt on these springs but many have used them successfully. Outside of Steve C. saying I need more pressure, any other concerns?

My old 5/16" .080 wall pushrods ended up producing an acceptable pattern on the valve stem so I would like to use them. However, Cliff did mention that he sees witness marks from flex so both he and Paul are recommending the .116 wall pushrods. I'm leaning towards replacing them but this has already cost a fortune........thoughts?

I already took a fine file to the cam gear to take the sharp edges off. I run the 80psi pump with a squirter in the gallery plug. I really don't have much of a choice but any concerns running the BOP gear?

[David Jones]

Butlers .116 pushrods are $129.....I think.

[74Grandville]

is a mega brace required with this cam? I'd worry more about the lifter bores then the springs.

[PAUL K]

If your .080 wall pushrods are the correct length, by all means you should use them.

[tom s]

I run the road paver with 200 on the seats and 600 open with no brace.That small of cam and little spring pressure wont need it.Tom

[Will]

Originally Posted by 74Grandville

is a mega brace required with this cam? I'd worry more about the lifter bores then the springs.

Not even close.

No worries until approaching 200 duration at .200" lift.

[grandville455]

Use the 116 wall pushrods, From Mike jones of jones racing cams , when I was running the hybrid setup...

With a hydraulic roller cam, running solid roller lifters. If you're hot lash is more then .006" x Rocker Ratio, you're off the end of the ramp, and not doing your valvetrain any good, so if you have to go to .003" cold, to keep the lash point below .006" x Rocker Ratio, then set it at .003"

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[Steve C.]

If measured and confirmed, there should be no issues with 160 lbs pressure. A fwiw, my Comp Cams Rep recommends at least 150 lbs minimum after run in with that set up.


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[Steve C.]

Personally if it were my project I would verify the actual spring pressure, not guess. Measure them with their retainers in place at the actual measured and verified installed height on the cylinder heads with a Rimac machine. Never trust catalog stated pressures, they can and do vary.



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[tom s]

Steve,I'm going to run 180 on the seats with the hyd rollers!Tom

[PAUL K]

Originally Posted by tom s

Steve,I'm going to run 180 on the seats with the hyd rollers!Tom

That's how you make power with a hydraulic roller!

[Formula8]

Thanks Guys. I almost forgot to mention the valley pan. I have the 66290-H16 lifters and a late model valley pan. Any clearance problems with this combination?

[Formula8]

Originally Posted by Steve C.

Personally if it were my project I would verify the actual spring pressure, not guess. Measure them with their retainers in place at the actual measured and verified installed height on the cylinder heads with a Rimac machine. Never trust catalog stated pressures, they can and do vary.
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I hear you and if the combination was untried, I would do that. However, many folks are running this exact cam with this exact spring in these heads at a marginally higher IH without an issue. So to some extent, whatever actual measured pressure they are at seems to work for others. I don't know if I would characterize using Crane's specs and using the calculations at your IH and open lift as a guess but I acknowledge, a measurement would be best.

Now I could run into a bad spring but they worked well with the previous cam and only have a couple hundred miles on them.

[tom s]

I also say you should have more pressure!Lofting roller lifters is hard on the valve train.Really no down side and only upside.Tom

[Formula8]

Originally Posted by tom s

I also say you should have more pressure!Lofting roller lifters is hard on the valve train.Really no down side and only upside.Tom

Outside of increasing the need for the thicker wall pushrods, probably pulling the heads for a spring change, resetting the IH, replacing the head and intake gaskets, springs and possibly spring retainers. Cliff claims to be running up to 6000 with slightly lower pressures (either he or Dave B. posted earlier 140-145/380 @ IH 1.790-1.810 according to my notes). I'm planning on setting my rev limiter at 5800 and using a factory intake this time around. IIRC, there are not a lot of springs that increase pressure while fitting in essentially the same space. It makes sense to consider replacing the springs with something else next time my heads are off.

[grandville455]

I have verified those same springs at a IH of 1.750 their only at 145, so your's being taller yet will be a tad less. I also tested mine at 1.800 and they were only 130, those springs only had 7 passes on them too. My car was fine , u will be too..

[Steve C.]

My statement- "Never trust catalog stated pressures, they can and do vary"

Here is a personal example from a previous set of Lunati valve springs I purchased. They were rated in the spec sheet to be 200 lbs seat pressure at 1.850" installed height. When measured on a Rimac machine they actually measured much higher. I called the shop I bought them from and they removed two sets from their shelf, same batch of springs mine came from. They were around 230 lbs at 1.900". If installed at the lower rated installed height they would of been way off. They went on the cylinder heads at 1.917"-1.920" installed height with 219-220 lbs.

My Crane spec sheet on hand suggests the 99893 spring is 167 lbs at 1.750" and 149 lbs at 1.800". Are we guessing what they are going to be at 1.770" installed height ?

From the Crane catalog.... "Note: Spring tensions often vary measurably within the same production runs; therefore it is recommended that EACH SPRING BE TESTED on an accurate spring tester and the springs installed at the recommended SEAT PRESSURE"

My engine builder checks new valve springs before he installs them. NEVER trust the published figures ! And very important springs can lose pressure after run in and over time. Personally we check my valve springs once a year at the same time we check the valve lash.

You lose enough spring pressure and the lifter loses contact on the lobe as the valve closes, if this is the situation .... and note this is important..... after time the springs will further deteriorate to the point it can cause issues other than nosing over at rpm. When people call it 'valve float', more often than not this is what happens.

Always run enough seat pressure to control the valve action as it returns to the seat. Heavier valves require more seat pressure. Strong, lightweight valves require less seat pressure. When in doubt, run slightly more seat pressure . . . not less.

And yes, in the opinion of many 160 lbs seat pressure on a solid roller set up could be marginal.

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[Steve C.]

Darby....

So that there is no misunderstanding, and possibly to correct my notes on hand.

I'm of the impression that when you tested your 99893 springs years ago and they tested at only 130 lbs that your car at the time was showing signs of nosing over at rpm on the track. And that is why you put in new springs.

If this is incorrect, my apologies for communicating in the past that was the situation.



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[grandville455]

Steve I think it was more cause i was having issues with the hyd lifters and was sick of the ticking etc? So Then I checked my old ones when going to the hybrid setup, and thats when i bought new, and then had them checked at my New IH?

[Torquewar]

Great thread.
Have some new solid Morels and a OF that i have been running. Looking at spring pressures now....Like your thoughts on this Steve.